Systems, methods and apparatus for improved management and control of energy delivery systems

ABSTRACT

Embodiments provide systems, methods and apparatus for controlling an energy delivery system including providing an energy management system (EMS) having an automatic generation control (AGC) system including a load frequency control (LFC) module; executing two or more performance standard functions implemented within the LFC module using input data regarding the energy delivery system, wherein at least one of the performance standard functions is defined to be dependent upon another of the performance standard functions; and implementing corrections to the operation of the energy delivery system based upon solution results of executing the performance standard functions. Numerous other aspects are provided.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 62/082,804 titled “Coordinated CPS Control” filed Nov. 21, 2014,which is incorporated herein by reference for all purposes.

FIELD

The present invention relates to operating energy delivery systems, andmore specifically to improved management and control of such systems.

BACKGROUND

An energy management system (EMS) is a system of computer implementedtools used by operators of electric utility grids to monitor, control,and optimize the performance of the generation and/or transmission of anenergy delivery system. In other words, an EMS optimizes, supervises andcontrols the transmission grid and generation assets. The monitoring andcontrol functions are known as “supervisory control and dataacquisition” (SCADA). Primary frequency control involves autonomousautomatic actions by the EMS to arrest deviations in power systemfrequency whenever imbalances arise between load and generation. Primaryfrequency control actions are fast; they are measured in megawatt(MW)/seconds. Primary frequency control actions include governorresponse, load damping, and voluntary frequency-responsive load control,all of which contribute to frequency response. Secondary frequencycontrol involves centrally coordinated actions by the EMS to returnfrequency to its scheduled value. Secondary frequency control actionsare slower than primary frequency control actions; they are measured inMW/min. They are deployed both during normal operations and afterprimary frequency control resources have arrested frequency followingmajor disturbances. Secondary frequency control actions includegeneration (or load) that responds to automatic generation control (AGC)signals or to operator dispatch commands. AGC is often referred to as“regulation” service.

In 2007, the Federal Energy Regulatory Commission (FERC) made compliancewith the North American Electric Reliability Corporation's (NERC)reliability standards, which include control performance standard 001(CPS1) and control performance standard 002 (CPS2) mandatory onregistered entities pursuant to the new authorities for reliability,which had been given to the FERC by the United States Congress throughthe Energy Policy Act of 2005. Thus, Independent System Operators (ISOs)of electrical power networks are required to monitor and operate withincertain power generation performance standards.

Beyond the CPS standards, the industry recognized that, from thestandpoint of improving reliability, there are benefits to monitoringfrequency error in time frames of less than one minute. This meant thatpractices which focus on managing area control error (ACE) and frequencyover time frames of longer than one minute, would not, by themselves, beeffective in ensuring reliability. For example, CPS1 does not providestrong incentives for short-term control because it is based onperformance averaged over the course of an entire year. Since CPS1 wasnot intended to serve this purpose, the industry has developed thebalancing authority ACE limit (BAAL) to address ACE and frequencyexcursions of shorter duration, as a supplement to CPS1. BAAL seeks toaddress all significant ACE and frequency deviations accounting for ACEdiversity.

These performance standards determine the amount of imbalance that ispermissible for reliability on power networks. Currently, ISOs operateby reacting to power trends as well as scheduled power interchange.Typically, operators provide regulatory agencies with scheduleinformation detailing the quantity of energy and the time that energywill be produced. These schedules of energy vary over the course of ayear, month, week, day, hour and other intervals of time such as seasonsand special days such as holidays and weekends. Despite knowing thatsuch energy requirements vary considerably at times, operators are oftentasked with the burden of meeting demand for real-time and unanticipatedshortage in energy. Having to meet these unanticipated demands is oftenthe cause of increased energy costs. Under certain circumstances, energycosts may decrease when an oversupply of energy exists in themarketplace.

Thus, there is a significant need to comply with the control performancestandards (CPS) (e.g., CPS1, CPS2, and BAAL) set by regulatoryauthorities such as the NERC. Therefore, what is needed are systems,methods and apparatus for improved management and control of energydelivery systems.

SUMMARY

In some embodiments, a method of controlling an energy delivery systemis provided. The method includes providing an energy management system(EMS) having an automatic generation control (AGC) system including aload frequency control (LFC) module; executing two or more performancestandard functions implemented within the LFC module using input dataregarding the energy delivery system, wherein at least one of theperformance standard functions is defined to be dependent upon anotherof the performance standard functions; and implementing corrections tothe operation of the energy delivery system based upon solution resultsof executing the performance standard functions.

In other embodiments, an energy management system (EMS) is provided. TheEMS includes a process controller; and a memory coupled to the processcontroller and storing instructions executable on the processcontroller, the instructions operable to execute two or more performancestandard functions implemented within an LFC module using input dataregarding an energy delivery system, wherein at least one of theperformance standard functions is defined to be dependent upon anotherof the performance standard functions; and implement corrections to theoperation of the energy delivery system based upon solution results ofexecuting the performance standard functions.

In still other embodiments, a load frequency control (LFC) module withinan automatic generation control (AGC) system is provided. The LFC moduleincludes a LFC application operative to execute on a process controllerto generate an output data structure and to store solution results in anoperational database of a EMS; and a coordinated CPS control engineoperable to execute on the process controller to receive input data,execute two or more performance standard functions called by the LFCapplication, and to populate the output data structure with solutionresults. At least one of the performance standard functions executableby the coordinated CPS control engine is defined to be dependent uponanother of the performance standard functions.

Numerous other aspects are provided in accordance with these and otheraspects of the invention. Other features and aspects of the presentinvention will become more fully apparent from the following detaileddescription, the appended claims and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram depicting a portion of an example energydelivery system according to embodiments of the present invention.

FIG. 2 is a block diagram of details of an example energy managementsystem according to embodiments of the present invention.

FIG. 3 is a flowchart depicting an example method according toembodiments of the present invention.

FIG. 4 is a flowchart depicting details of a portion of the examplemethod of FIG. 3 according to embodiments of the present invention.

DESCRIPTION

Embodiments of the present invention provide systems, apparatus andmethods for an improved energy management system (EMS) for electricitydelivery, or more generally, energy delivery systems. Embodiments of thepresent invention include software applications and systems adapted toprovide an enhanced automatic generation control (AGC) system viaimprovements to a load frequency control (LFC) module. The LFC moduleimprovements include coordinating a CPS based control function and apredictive CPS control function. These improvements are responsible fordetermining the appropriate amount of system regulation required forregulating area frequency and interchange so that a control area'sperformance meets the NERC control performance standards.

Embodiments of the invention provide systems that operate using theoverall twelve month CPS1 performance statistics and the overall monthlyCPS2 performance statistics to meet NERC Control Performance Standard(CPS) requirements, for example where both the CPS1 performancerequirement and the CPS2 performance requirement are enforced. In otherembodiments, systems are provided that operate using the overall twelvemonth CPS1 performance statistics to meet the NERC CPS1 performancerequirement and the control area's clock-minute average of reporting ACEdoes not exceed its clock-minute Balancing Authority ACE Limit (BAAL)for more than thirty consecutive clock minutes.

In some embodiments, the improved LFC module supports a new approach ofcomputing control actions. For example, a control area's control actioncan be determined based on several factors such as the overall runningCPS1 performance statistics over the past eleven months and the currentmonth until the current time; the instantaneous CPS1 performancestatistics for the current clock minute; the overall running CPS2performance statistics over the current month till the current time; theinstantaneous CPS2 performance statistics for the current clock tenminute time period; and/or the number of consecutive clock minutes forwhich clock-minute ACE average exceeds the control area's BAAL limit(e.g., depending on whether CPS2 is applicable or the BAAL limit isapplicable).

Further, in the case where both CPS1 and CPS2 requirements areapplicable, the long-term CPS1 control and CPS2 control andshort-term-term CPS1 control and CPS2 control are integrated instead ofbeing independent. The long-term CPS1 control and CPS2 control no longerdirectly impose control actions. The short-term CPS1 control and CPS2control take guidance from the long-term CPS1 control and CPS2 control.The clock-minute ACE target from the long-term CPS1 control and theclock-ten-minute ACE target from the long-term CPS2 control ensure thatif there are control actions required, they are significant factors toconsider in determining to where the ACE should be driven down. In thecase where the CPS1 requirement and the BAAL limit are applicable, theshort-term CPS1 control and the long-term CPS1 control are applicable;and in addition, instead of CPS2 control, the ACE correction withrespect to the BAAL limit is applied. In some embodiments, the controlarea's corrective control action is progressive, but can be aggressivedepending on how good or bad the overall running control performancestatistics are relative to the control area's specified performancestargets and the NERC control performance requirements.

Turning now to FIG. 1, a portion of an example energy deliver system 100according to embodiments of the present invention is provided.Independent System Operators (ISO) 102 operate control centers that caninclude an EMS 104. The EMS 104 can include a number of hardware andsoftware components for monitoring, controlling, and optimizing theperformance (e.g., in terms of minimizing cost, maximizing efficiency,and maximizing reliability) of the generation and transmission of theenergy delivery system 100.

The EMS 104 includes an automatic generation control (AGC) system 106for adjusting the power output of multiple resources 108 (e.g.,generators) at different power plants (e.g., utilities 110, independentpower producers (IPP) and/or non-utility generators (NUG) 112, etc.), inresponse to changes in the load created by consumers of the electricity.The generated power is delivered from the resources 108 to consumers viatransmission lines 114. Note that the utilities 110 can include an EMS104 with an AGC system 106. IPPs and/or NUGs 112 can allow the ISO's AGCsystem 106 to control the IPPs' and/or NUGs' resources 108 but willinclude at least some form of management system 116.

Since a power grid requires that generation and load closely balancemoment by moment, frequent adjustments to the output of resources 108are continuously made. The balance can be judged by measuring the systemfrequency; if system frequency is increasing, more power is beinggenerated than used, and the generators in the system 100 areaccelerating. If the system frequency is decreasing, more load is on thesystem 100 than the instantaneous generation can provide, and thegenerators in the system 100 are slowing down.

Where the grid has tie interconnections to adjacent control areas, theAGC system 106 helps maintain the power interchanges over the tie linesat the scheduled levels. With computer-based control systems andmultiple inputs, an AGC system 106 can take into account such matters asthe most economical units to adjust, the coordination of thermal,hydroelectric, and other generation types, and constraints related tothe stability of the system and capacity of interconnections to otherpower grids.

As indicated above, power utilities 110 and ISOs 102 are committed tocontrolling the generating resources 108 in their control areas invarious optimized ways in order to meet the NERC mandated CPS1performance requirement and either the CPS2 control performancerequirement or the BAAL compliance requirement. In embodiments of thepresent invention, the running CPS1 performance statistics and eitherthe CPS2 performance statistics or the running BAAL performancestatistics are fed back into the control mechanism (e.g., the EMS 104)to ensure that at the end of each twelve month time period the overallyearly control performance statistics are satisfactory and eithermonthly CPS2 performance or the BAAL compliance performance issatisfactory.

Note that currently, some power utilities are using the CPS1 performancerequirement with the BAAL requirement while others are applying the CPS1performance requirement and the CPS2 performance requirement. It isanticipated that it may be several years for use of the BAAL requirementto entirely replace use of the CPS2 performance requirement. Thus,embodiments of the present invention include embodiments for meeting theCPS1 and CPS2 performance requirements, and embodiments for meeting theCPS1 and BAAL performance requirements. Note that use of the CPS1 iscommon to all embodiments.

Within the AGC systems of existing commercially available EMS productssuch as the Spectrum Power 3™ and the Spectrum Power TG™ EnergyManagement Systems manufactured by Siemens Industry, Inc. of Washington,D.C., load frequency control (LFC) modules can be included that provideCPS based control and predictive CPS control. However, existing CPSbased control is short term based and only incorporates the currentinstantaneous CPS1 performance and the CPS2 performance into the AGCsystem control. Existing predictive CPS control is long term based. Itonly considers the running CPS1 performance and the CPS2 performance toa limited degree (that is, 11 months in the past and the current monthuntil the current moment for CPS1, and the current month till thecurrent moment for CPS2) and incorporates them into the AGC systemcontrol. These two controls execute independently and are not affectedby each other. In other words, the output of the CPS based control doesnot influence the output of the predictive CPS control and vice versa.There can be disadvantages of these two controls operating independentlyof each other.

For the short term based CPS control, the prior art control only reactsto the current instantaneous CPS performance statistics: if theperformance statistics are good enough, looser control is exercised;otherwise, tighter control is exercised. The prior art control does notconsider how the current instantaneous CPS performance statistics shouldaffect the overall CPS performance statistics. In the end, the overallperformance statistics may be too good which means excessively tightcontrol has been exercised (e.g., incurring unnecessary extra expense);or the overall performance statistics may not be good enough which meansthat opportunities have been lost when tighter control should have beenexercised.

For the long term based CPS control, the control is aware of what theoverall CPS1 and CPS2 performance statistics are and the control reactsto them. The control is not as responsive as the short term based CPScontrol. There are scenarios that require immediate corrections (e.g.,ACE is consistently beyond a certain threshold for some time) so thesituation does not get worse or even out of control.

In embodiments of the present invention, the short term based CPScontrol function and long term based CPS control function arecoordinated and operate together to achieve the desired overall CPSperformance levels and yet respond properly to instantaneous CPSperformance statistics in a smooth manner (e.g., without takingunnecessary corrective actions).

In some embodiments, the LFC module is a cyclical executing program witha generation control cycle time of a few seconds (e.g., 2 seconds, 4seconds, 6 seconds). The LFC module is operative to have the long termbased CPS control function compute the one-minute ACE target andten-minute ACE target; and to have the short term based CPS controlfunction make use of these ACE targets and to calculate system MWcontrol corrections for CPS1 and CPS2 and the total correctionsrequired.

In the case where the BAAL performance standard is applied in place ofthe CPS2 performance standard, the BAAL control scheme is develop tocalculate clock-minute ACE and clock-minute BAAL, monitor theclock-minute ACE average, and initiate control action to correct ACEback with the clock-minute BAAL if it exceeds clock-minute BAAL.

Turning now to FIG. 2, an example configuration of an EMS 104 (e.g., anEMS 104 operated by an ISO) that supports operation of an improved AGCsystem 106 according to embodiments of the present invention is shown.The AGC system 106 includes a Load Frequency Control (LFC) module thatimplements a coordinated CPS control engine, the functions of which aredescribed in detail below. The AGC system 106 can be implemented withina Process Controller (PC) server 202 that also includes Communicator(COM) functionality. The EMS 104 can include redundant back-up serversto provide higher reliability and fault-tolerance. Thus, a Standby (SB)server 204 is also provided. A PC server 206 that implements aHistorical Information System (HIS) includes a CPS database (DB) 208that is accessible by (e.g., communicatively coupled to) the LFC modulein the AGC system 106. A SB server 210 implements a backup HIS thatincludes a backup CPS DB 212. The LFC module in the AGC system 106 isalso adapted to access the backup CPS DB 212 of the SB server 210.Likewise, the LFC module of the backup AGC system 106 on the SB server204 is adapted to access (e.g., is communicatively coupled to) both theCPS DB 208 of the PC server 206 with the HIS and the SB server 210 withthe backup HIS that includes a backup CPS DB 212.

EMS 104 further includes one or more Utility Communication Servers 214that each provide an implementation of an Inter-Control CenterCommunication Protocol (ICCP) 216 that enables communication with, forexample, other EMSs in operation at, for example, several utilities 110(FIG. 1). In some embodiments, ICCP 216 can be used to implement remotecontrol of resources 108 (FIG. 1) by implementing AGC system 106communications between different EMSs. The EMS 104 also includes acommunication front end (CFE)/Real Time Data Server (RIDS) 218 tofacilitate communications with external entities and users via remoteterminal units (RTUs) 220. Note that RTUs 220 are part of the powerutilities' field devices, for example.

In operation, the ISO clears the real time market through its marketoptimization engine and then the ISO dispatches instructions along withancillary service awards (e.g., regulation, reserves, etc.) toindividual power utilities through a transport mechanism (e.g., ICCP216). The power utilities receive the dispatch instructions (e.g., viaICCP 216) and then make use of their AGC 106 to compute a power setpointcommand for each AGC cycle for the resources under AGC control (i.e.,AGC units). Next, the setpoints are updated to SCADA and they are thensent to the utilities' RTUs 220 via the CFE/RTDS 218. There arededicated RTU lines that connect the RTUs to the CFE/RTDS 218 via, e.g.,modems. Typically, RTUs are geographically located in the utilities'substations and hardwired to the resources (e.g., generators). Thevarious applications such as, for example, AGC 106, SCADA, CFE/RTDS 218,and ICCP 216 are part of EMS 104. The RTUs 220 are field devices thatare capable of sending telemetry to ISO EMS 104 and can also receivemegawatt (MW) setpoints from the ISO EMS 104 to control resources (e.g.,generators).

In some embodiments, the EMS 104 can include a number of additionalservers and applications. For example, the EMS 104 can include OperatorTraining Simulator (OTS) servers 222, Man-Machine Interface (MMI)servers 224, a PC Administration (ADM) application server 226, a SB ADMapplication server 228, a PC Transmission Network Application (TNA) 230,and a SB TNA 232.

In some embodiments, the functions of the LFC module can include a LongTerm CPS1 Control function, a Short Term CPS1 Control function, a LongTerm CPS2 Control function, a Short Term CPS2 Control function, a BAALControl function, a Prioritization of CPS1 and CPS2 Control function,and a Prioritization of CPS1 and BAAL Control function.

The Long Term CPS1 Control function makes use of the overall CPS1performance statistics over the past eleven months and the current monthuntil the current moment and employs probability theory to determine theone-minute ACE target for short term CPS1 control.

The Short Term CPS1 Control function incorporates the one-minute ACEtarget derived from the Long Term CPS1 Control function and determinesthe control effort needed to achieve CPS1 control.

According to embodiments of the present invention, along with the LongTerm CPS1 Control function and the Short Term CPS1 Control function,either the two CPS2 control functions can be used or the BAAL Controlfunction can be used.

The Long Term CPS2 Control function makes use of the overall CPS2performance statistics over the current month till the current momentand employs probability theory to determine the ten-minute ACE targetfor short term CPS2 control.

The Short Term CPS2 Control function incorporates the ten-minute ACEtarget derived from the Long Term CPS1 Control function and determinesthe control effort needed to achieve CPS2 control.

The BAAL Control function incorporates the safer BAAL target, which ismore conservative than the BAAL high limit or low limit, and employs thesafer BAAL target to determine the control effort needed to achieve BAALcontrol.

The Prioritization of CPS1 and CPS2 Control function operates accordingto a rule set based on the relative status of the CPS corrections. Ifthe CPS1 correction and the CPS2 correction are in the same direction(e.g., both indicating generation frequency should be increased byadding generation/regulation or both indicating generation frequencyshould be decreased by reducing generation/regulation), the greatercorrection is used. If the CPS1 correction and the CPS2 correction arein the opposite directions, the CPS2 correction is used for control. Ifthere is a CPS1 correction and no CPS2 correction, the CPS1 correctionis used. If there is a CPS2 correction and no CPS1 correction, the CPS2correction is used.

The Prioritization of CPS1 and BAAL Control function operates accordingto a rule set based on the relative status of the CPS1 and BAALcorrections. If the CPS1 correction and the BAAL correction are in thesame direction, the greater correction is used. If the CPS1 correctionand the BAAL correction are in the opposite directions, the BAALcorrection is used for control. If there is a CPS1 correction and noBAAL correction, the CPS1 correction is used. If there is a BAALcorrection and no CPS1 correction, the BAAL correction is used.

In order to achieve the objectives of economically dispatch generatingunits among economically dispatchable generating units and economicallyallocating regulation among regulating units and yet incur the only theminimum number of generating units movements (e.g., corrections), twosets of algorithmic procedures are provided by embodiments of thepresent invention and these procedures work together in a coordinatedmanner.

The functions of the LFC module listed above are now described indetail. The Long Term CPS1 Control function determines the ten-minuteACE target for the next clock ten-minute time period. NREC CPS1 standardis defined as:

${{AVG}_{12\text{-}{month}}\left\lbrack {\left( \frac{{ACE}_{i}}{{- 10}B_{i}} \right)_{i}\Delta\; F_{i}} \right\rbrack} \leq ɛ_{1}^{2}$or equivalently,

${{CPS}\; 1} = {{\left( {2 - {{{AVG}_{12\text{-}{month}}\left\lbrack {\left( \frac{{ACE}_{i}}{{- 10}B_{i}} \right)_{i}\Delta\; F_{i}} \right\rbrack}/ɛ_{1}^{2}}} \right) \times 100\%} \geq {100\%}}$where AVG_(i)=the 12 month average;

ACE_(i)=the clock-minute average of ACE;

B_(i)=the frequency bias of the control area;

ε_(i) is the interconnections' targeted frequency bound; and

ΔF_(i) is the clock-minute average frequency error.

A 12-month time period T has (n_(T)=365 days/year×24 hours/day×601-minute intervals/hour) 525600 clock-minute time intervals. Let n_(t)denote the number of clock-minute time intervals till now within theinteresting 12-month time period T. Let n_(T−t) designate the number ofremaining clock-minute time intervals till the end of period T. Letn_(T) designate the number of total clock-minute time intervals withinthe time period T. To simplify the derivation that follows, we define

$X = \left\lbrack {\left( \frac{{ACE}_{i}}{{- 10}B_{i}} \right)_{i}\Delta\; F_{i}} \right\rbrack$Then CPS1 standard can be equivalently expressed in probability terms asX=E{X}≤ε ₁ ²with the common-sense assumption that the expectation of X equals itstime average over a sufficiently long time period.

Let the average of X during the n_(t) clock-minute time period bedenoted by X ₁, and let the average of X during the remaining n_(T−t)clock-minute time period be denoted by X ₂. Then we have the following:

$\overset{\_}{X} = {{{\frac{n_{t}}{n_{t} + n_{T - t}}{\overset{\_}{X}}_{1}} + {\frac{n_{T - t}}{n_{t} + n_{T - t}}{\overset{\_}{X}}_{2}}} \leq ɛ_{1}^{2}}$Notice that n_(T)=n_(t)+n_(T−t), and n_(t), n_(T−t) and n_(T) are allknown, and X ₁ can be computed as

${{AVG}_{n_{t}{Clock}\text{-}{MinuteTimeIntervals}}\left\lbrack {\left( \frac{{ACE}_{i}}{{- 10}B_{i}} \right)_{i}\Delta\; F_{i}} \right\rbrack}.$Therefore,X ₂≤[(n _(t) +n _(T−t))ε₁ ² −n _(t) X ₁ ]/n _(T−t)where X ₂ presents statistical target for

$\left\lbrack {\left( \frac{{ACE}_{i}}{{- 10}B_{i}} \right)_{i}\Delta\; F_{i}} \right\rbrack$for the remaining n_(T−t) clock-minute time horizon. Note that thistarget can be lower or higher depending on the CPS1 performance untilthe current moment.

To further compute the CPS1 based control target, we require that forevery clock-minute,

$\left\lbrack {\left( \frac{{ACE}_{i}}{{- 10}B_{i}} \right)_{i}\Delta\; F_{i}} \right\rbrack \leq {\left\lbrack {{\left( {n_{t} + n_{T - t}} \right)ɛ_{1}^{2}} - {n_{t}{\overset{\_}{X}}_{1}}} \right\rbrack/{n_{T - t}.}}$

If this is satisfied for every clock-minute for the remaining n_(T−t)clock-minute time horizon, then we can achieve the desired performanceX ₂≤[(n _(t) +n _(T−t))ε₁ ² −n _(t) X ₁ ]/n _(T−t).

The previous clock-minute average frequency error ΔF_(i) can be used asthe current clock-minute average frequency error in order to calculatethe current clock-minute ACE target which in turns determines theeventual CPS1 based control amount. Consequently,

$\left\lbrack {\left( \frac{{ACE}_{i}}{{- 10}B_{i}} \right)_{i}\Delta\; F_{i}} \right\rbrack \leq {\left\lbrack {{\left( {n_{t} + n_{T - t}} \right)ɛ_{1}^{2}} - {n_{t}{\overset{\_}{X}}_{1}}} \right\rbrack/n_{T - t}}$Therefore,

If ΔF_(i)>0, thenACE_(i)≤{[(n _(t) +n _(T−t))ε₁ ² −n _(t) X ₁ ]/n _(T−t)}(−10B _(i))/ΔF_(i)

If ΔF_(i)<0, thenACE_(i)≥{[(n _(t) +n _(T−t))ε₁ ² −n _(t) X ₁ ]/n _(T−t)}(−10B _(i))/ΔF_(i)To be less aggressive, the largest clock-minute average frequency errorΔF_(i) (in absolute value), denoted by(ΔF _(i))_(m)=max_(i)({|ΔF _(i)|})sign(ΔF _(i)),among the past larger time period (for instance, the previous 30-minutetime period) can be used. In either case, the clock-minute ACE target iscalculated asACE_(i)={[(n _(t) +n _(T−t))ε₁ ² −n _(t) X ₁ ]/n _(T−t)}(−10B _(i))/(ΔF_(i))_(m)μ₁ =|A{[(n _(t) +n _(T−t))ε₁ ² −n _(t) X ₁ ]/n _(T−t)}(−10B _(i))/(ΔF_(i))_(m)|or −μ₁ represents the clock-minute ACE target depending on the sign ofthe eventual clock-minute ACE average for the future clock minute. Theseclock-minute ACE targets are calculated every minute. Note that μ₁cannot be too large, if it is greater than L₁₀, then μ₁=L₁₀.

Besides the CPS1 performance standard requirement of 100% compliance(CPS1_(NERC) ^(Target)=100%), each control area has its own CPS1performance target CPS1_(CA) ^(Target) which must be higher thanCPS1_(NERC) ^(Target). Let the overall running CPS1 performance over thepast eleven months and current month until the current moment be denotedby CPS1_(CA) ^(Overall).

There is no long-term CPS1 control action if CPS1_(CA)^(Overall)>CPS1_(CA) ^(Target). For all other cases, the long-term CPS1control action will be incorporated in the short-term CPS1 controlaction, which is detailed in the Short Term CPS1 Control function below.

The Long Term CPS2 Control function determines the one-minute ACE targetfor the next clock-minute time period. CPS1 and CPS2 performance indicesare checked yearly or monthly and based on 1-minute or 10-minuteaverage, i.e. time integral values of ACE. In prior art approaches, timeweighting factors are used to accommodate control strategy to alreadyprocessed and future expectations of ACE values.

A real-time control strategy can be based on solid foundations ofprobability theory. Embodiments of the present invention determine howto proceed with inter-temporal adjustments in the least statisticallycorrect way. Note that the CPS based AGC is a fully statistical problemexpressed in probability terms. In particular, NERC requires 90%compliance of 10-minute ACE averages over 1 month. The CPS2 standard canbe defined as:Avg_(10-minute)[ACE_(i) ]≤L ₁₀Where:

-   -   ACE_(i) is the instantaneous tie-line bias ACE value        L ₁₀ =L _(pr)·ε₁₀·√{square root over ((−10B _(i))(−10B _(s)))}        -   ε₁₀ is the constant derived from the targeted frequency            bound.        -   L_(pr) is the constant equal to 1.65 used to convert the            frequency target to 90% probability        -   B_(i) is the frequency bias of the Control Area        -   B_(s) is the frequency bias of the interconnection.

One month has (for example, in case of a 30-day month, 30 days×24hours×6 10-minute intervals) T=4320 10-minute time intervals. Let thecurrent time interval be denoted by t. Let until this time n_(t) denotenumber of valid ACE_(10-min) values and v_(t) represent the number ofthem that are CPS2 violations. Let n_(T−t) denote the number ofremaining time intervals until the end of period T, and assume therewill be v_(T−t) CPS2 violations. To comply with the CPS2 standard with90% at the end of T time intervals the following relation should besatisfied:

$\frac{v_{t} + v_{T - t}}{n_{t} + n_{T - t}} \leq 0.1$ or${\frac{v_{T - t}}{n_{T - t}} \leq {0.1 + \frac{{0.1 \cdot n_{t}} - v_{t}}{n_{T - t}}}} = p_{T - t}$where P_(T−t) presents probability target for the remaining T−t timehorizon. Note that this target can be lower or higher than 0.1 dependingon performance until the moment t.

CPS2 criteria can be expressed in probability terms as:P{|[ACE₁₀ ]|≤L ₁₀}0.9Where [ACE₁₀ ] is a random variable that represents 10-minute ACEaverage over 1 month.

Let B₁₀=ε₁₀√{square root over ((−10B_(i))(−10B_(s)))}

Then L₁₀=1.65B₁₀

It is assumed in NERC's CPS criteria derivation that [ACE₁₀ ] has anormal distribution with its expectation 0 and standard deviation σ_([)_(ACE) ₁₀ _(]) whereσ_([) _(ACE) ₁₀ _(]) ² =E{[ACE₁₀ ]²}

To simplify, normalize [ACE₁₀ ] such thatace₁₀=[ACE₁₀ ]/σ_([) _(ACE) ₁₀ _(])Then ace₁₀ has a standard normal distribution with expectation 0 andstandard deviation 1, and its probability density function is

${p(x)} = {\frac{1}{\sqrt{2\pi}}\exp\left\{ {- \frac{x^{2}}{2}} \right\}}$

Now CPS2 criteria can be rewritten in terms of ace₁₀ as follows:P{|ace₁₀ |≤L ₁₀/σ_([) _(ACE) ₁₀ _(])}≥0.9Note that for any non-negative y, there exists a unique non-negative xsuch that

${P\left\{ {{{ace}_{10}} \leq x} \right\}} = {{\frac{1}{\sqrt{2\pi}}{\int_{- x}^{x}{\exp\left\{ {- \frac{t^{2}}{2}} \right\}{\mathbb{d}t}}}} = y}$Then ifL ₁₀/σ_([) _(ACE) ₁₀ _(]) ≥x,we haveP{|ace₁₀ |≤x}≥y

Let y be a target for expected CPS2 compliance as calculated above, thatis,

${y = {p_{T - t} = {0.1 + \frac{{0.1 \cdot n_{t}} - v_{t}}{n_{T - t}}}}},$the normalized ace₁₀ target x can be immediately computed (for example,when y=0.9, we have x=1.65).WithL ₁₀/σ_([) _(ACE) ₁₀ _(]) ≥x,we haveσ_([) _(ACE) ₁₀ _(]) ≤L ₁₀ /x,Since σ_([) _(ACE) ₁₀ _(]) can be calculated using an average approach(approximation of expectation of [ACE₁₀ ]²), we can readily calculatethe CPS2 ACE-10 control target for the next 10-minute period.

${\left( {{\sum\limits_{i = 1}^{t - 1}\left\lbrack \overset{\_}{{ACE}_{10}} \right\rbrack_{i}^{2}} + \left\lbrack \overset{\_}{{ACE}_{10}} \right\rbrack_{t}^{2}} \right)/\left( {t - 1} \right)} = \left\lbrack \sigma_{\lbrack\overset{\_}{{ACE}_{10}}\rbrack} \right\rbrack^{2}$That is, from

$\sqrt{\left( {{\sum\limits_{i = 1}^{t - 1}\left\lbrack \overset{\_}{{ACE}_{10}} \right\rbrack_{i}^{2}} + \left\lbrack \overset{\_}{{ACE}_{10}} \right\rbrack_{t}^{2}} \right)/\left( {t - 1} \right)} = {L_{10}/x}$We have

${\left\lbrack \overset{\_}{{ACE}_{10}} \right\rbrack_{t}} = \sqrt{\left( {\left( {t - 1} \right) \times \left( {L_{10}/x} \right)^{2}} \right) - {\sum\limits_{i = 1}^{t - 1}\left\lbrack \overset{\_}{{ACE}_{10}} \right\rbrack_{i}^{2}}}$$\mu_{10} = \sqrt{\left( {\left( {t - 1} \right) \times \left( {L_{10}/x} \right)^{2}} \right) - {\sum\limits_{i = 1}^{t - 1}\left\lbrack \overset{\_}{{ACE}_{10}} \right\rbrack_{i}^{2}}}$

or −μ₁₀ represents the clock-ten-minute ACE target depending on the signof eventual clock-ten-minute ACE average for the future clock-ten-minutetime period. These clock-ten-minute ACE targets are calculated every tenminutes. Note that μ₁₀ cannot be too large, if it is greater than L₁₀,then μ₁₀=L₁₀; if μ₁₀ does not exist, then μ₁₀=L₁₀.

Besides the CPS1 performance standard requirement of 90% compliance(CPS2_(NERC) ^(Target)=90%), each control area has its own CPS2performance target CPS2_(CA) ^(Target) which must be higher thanCPS2_(NERC) ^(Target). Let the overall running CPS2 performance over thecurrent month till the current moment be denoted by CPS2_(CA)^(Overall).

There is no long-term CPS2 control action if CPS2_(CA)^(Overall)>CPS2_(CA) ^(Target). For all other cases, the long-term CPS2control action will be incorporated in the short-term CPS2 controlaction, which will be detailed in the Short Term CPS2 Control below.

The Short Term CPS1 Control function is next derived. The instantaneousCPS1 performance for the current LFC control cycle is calculated asfollows:

${{CPS}\; 1_{CA}^{Instant}} = {\left( {2 - {\frac{\overset{\_}{ACE}}{{- 10}\overset{\_}{B}}{\overset{\_}{\Delta\; F}/ɛ_{1}^{2}}}} \right) \times 100\%}$Where ACE is the running average ACE for the current clock minute, B therunning average frequency bias of the control area for the current clockminute, ε₁ the interconnection's targeted frequency bound, and ΔF therunning average frequency error for the current clock minute.

In some embodiments, the control scheme can be defined as follows. Ifthe overall CPS1 performance is better than the CPS1 target, that is,CPS1_(CA) ^(Overall)>CPS1_(CA) ^(Target),then the following three cases are differentiated: (A) If theinstantaneous CPS1 performance is better than the NERC CPS1 performancerequirement, that is, CPS1_(CA) ^(Instant)>CPS1_(NERC) ^(Target), thenthere is no control action from Short-Term CPS1 Control. (B) If theinstantaneous CPS1 performance is between the desired overall CPS1performance target and the NERC CPS1 performance requirement, that is,CPS1_(NERC) ^(Target)≤CPS1_(CA) ^(Instant)≤CPS1_(CA) ^(Target),then the correction for CPS1 is CPS1_Correction=−k₁(ACE−μ₁) for ACE>μ₁,or CPS1_Correction=−k₁(ACE+μ₁) for ACE<−μ₁, or no control action for−μ₁<ACE<μ₁; where k₁ is positive and tunable with a default value of0.2. (C) If the instantaneous CPS1 performance is less than the NERCCPS1 performance requirement, that is,CPS1_(CA) ^(Instant)<CPS1_(NERC) ^(Target),then the correction for CPS1 isCPS1_Correction=−k ₂(ACE−μ₁) for ACE>μ₁,orCPS1_Correction=−k ₂(ACE+μ₁)for ACE<−μ₁, or no control action for −μ₁<ACE<μ₁; where k₂ is positiveand tunable with a default value of 0.5.

If the overall CPS1 performance is between the CPS1 target and theminimum NERC CPS1 performance requirement, that is,CPS1_(NERC) ^(Target)<CPS1_(CA) ^(Overall)<CPS1_(CA) ^(Target),then the following three cases are differentiated: (A) If theinstantaneous CPS1 performance is better than the NERC CPS1 performancerequirement, that is, CPS1_(CA) ^(Instant)>CPS1_(NERC) ^(Target), thenthere is no control action from Short-Term CPS1 Control. (B) If theinstantaneous CPS1 performance is between the desired overall CPS1performance target and the NERC CPS1 performance requirement, that is,CPS1_(NERC) ^(Target)≤CPS1_(CA) ^(Instant)≤CPS1_(CA) ^(Target), then thecorrection for CPS1 is CPS1_Correction=−k₃(ACE−μ₁) for ACE>μ₁, orCPS1_Correction=−k₃(ACE+μ₁) for ACE<−μ₁, or no control action for−μ₁<ACE<μ₁; where k₃ is positive and tunable with a default value of0.4. (C) If the instantaneous CPS1 performance is less than the NERCCPS1 performance requirement, that is, CPS1_(CA) ^(Instant)<CPS1_(NERC)^(Target), then the correction for CPS1 is CPS1_Correction=−k₄(ACE−μ₁)for ACE>μ₁, or CPS1_Correction=−k₄(ACE+μ₁) for ACE<−μ₁, or no controlaction for −μ₁<ACE<μ₁; where k₄ is positive and tunable with a defaultvalue of 0.6.

If the overall CPS1 performance is less than the minimum NERC CPS1performance requirement, that is,CPS1_(CA) ^(Overall)<CPS1_(NERC) ^(Target),then the following three cases are differentiated: (A) If theinstantaneous CPS1 performance is better than the NERC CPS1 performancerequirement, that is, CPS1_(CA) ^(Instant)>CPS1_(NERC) ^(Target), thenthere is no control action from Short-Term CPS1 Control. (B) If theinstantaneous CPS1 performance is between the desired overall CPS1performance target and the NERC CPS1 performance requirement, that is,CPS1_(NERC) ^(Target)≤CPS1_(CA) ^(Instant)≤CPS1_(CA) ^(Target), then thecorrection for CPS1 is CPS1_Correction=−k₅(ACE−μ₁) for ACE>₁ orCPS1_Correction=−k₅(ACE+μ₁) for ACE<−μ₁, or no control action for−μ₁<ACE<μ₁; where k₅ is positive and tunable with a default value of0.7. (C) If the instantaneous CPS1 performance is less than the NERCCPS1 performance requirement, that is, CPS1_(CA) ^(Instant)<CPS1_(NERC)^(Target), then the correction for CPS1 is CPS1_Correction=−k₆(ACE−μ₁)for ACE>μ₁ or CPS1_Correction=−k₆(ACE+μ₁) for ACE<−μ₁, or no controlaction for −μ₁<ACE<μ₁; where k₆ is positive and tunable with a defaultvalue of 1.0.

Note that if the instantaneous ACE and the instantaneous frequencydeviation are in opposite directions, there is no need to take CPS1correction. If the instantaneous ACE in magnitude is more than thepre-designated emergency threshold (which can typically be a few timesas large as L₁₀), the corrective control action is to bring ACE to 0.

In the Short Term CPS2 Control function, the instantaneous CPS2performance is measured to compare the current clock-ten-minute ACEaverage to L₁₀ and then a check is made to determine if the average isless than L₁₀. The instantaneous CPS2 performance for the currentclock-ten-minute is either 0 or 100%. In some embodiments, the controlscheme for this function can be defined as follows.

If the overall CPS2 performance is better than the CPS2 target, that is,CPS2_(CA) ^(Overall)>CPS2_(CA) ^(Target),then the following two cases are differentiated: (A) If theinstantaneous CPS2 performance is 100%, then there is no control actionfrom Short-Term CPS2 Control. (B) If the instantaneous CPS2 performanceis 0% (which means the absolute value of the current clock-ten-minuteACE average is greater than L₁₀), then the correction for CPS2 isCPS2_Correction=−(ACE−k ₇ min(μ₁₀ ,L ₁₀−db))ifACE>min(μ₁₀ ,L ₁₀−db),orCPS2_Correction=−(ACE+k ₇ min(μ₁₀ ,L ₁₀−db))ifACE<−min(μ₁₀ ,L ₁₀−db),where k₇ is positive and tunable with a default value of 1.0, and db isa deadband applied to L₁₀.

If the overall CPS2 performance is between the CPS2 target and theminimum NERC CPS2 requirement, that is,CPS2_(NERC) ^(Target)<CPS2_(CA) ^(Overall)<CPS2_(CA) ^(Target),then the following two cases are differentiated: (A) If theinstantaneous CPS2 performance is 100%, then there is no control actionfrom Short-Term CPS2 Control. (B) If the instantaneous CPS2 performanceis 0% (which means the absolute value of the current clock-ten-minuteACE average is greater than L₁₀), then the correction for CPS2 isCPS2_Correction=−(ACE−k ₈ min(μ₁₀ ,L ₁₀−db))ifACE>min(μ₁₀ ,L ₁₀−db),orCPS2_Correction=−(ACE+k ₈ min(μ₁₀ ,L ₁₀−db))ifACE<−min(μ₁₀ ,L ₁₀−db),where k₈ is positive and tunable with a default value of 0.5.

If the overall CPS2 performance is less than the minimum NERC CPS2requirement, that is,CPS2_(CA) ^(Overall)<CPS2_(NERC) ^(Target),then the following two cases are differentiated: (A) If theinstantaneous CPS2 performance is 100%, then there is no control actionfrom Short-Term CPS2 Control. (B) If the instantaneous CPS2 performanceis 0% (which means the absolute value of the current clock-ten-minuteACE average is greater than L₁₀), then the correction for CPS2 isCPS2_Correction=−(ACE−k ₉ min(μ₁₀ ,L ₁₀−db))ifACE>min(μ₁₀ ,L ₁₀−db),OrCPS2_Correction=−(ACE+k ₉ min(μ₁₀ ,L ₁₀−db))ifACE<−min(μ₁₀ ,L ₁₀−db),where k₉ is positive and tunable with a default value of 0.

The BAAL Control function computes running clock-minute average, theclock-minute BAAL, compares the clock-minute average to the clock-minuteBAAL, and at the end of each clock minute, checks if there is BAALviolation. If so, then the count-down time for correcting the BAALviolation is 29 minutes (with 1 minute of BAAL violation alreadyassessed). The monitoring and control involves the following process.

The clock-minute average ACE is computed. The instantaneous BAAL iscomputed as follows.

${BAAL}_{Low} = {\left( {{- 10}{B_{i}\left( {{FTL}_{Low} - F_{S}} \right)}} \right) \times \frac{\left( {{FTL}_{Low} - F_{S}} \right)}{F_{A} - F_{S}}}$when actual frequency is less than scheduled frequency.

${BAAL}_{High} = {\left( {{- 10}{B_{i}\left( {{FTL}_{High} - F_{S}} \right)}} \right) \times \frac{\left( {{FTL}_{High} - F_{S}} \right)}{\left( {F_{A} - F_{S}} \right)}}$when actual frequency is greater than scheduled frequency. Note thatBAAL_(Low) or BAAL_(High) may apply, but not both. If actual frequencyis equal to Scheduled Frequency, neither of BAAL_(Low) and BAAL_(High)applies.

The relevant variables are defined as follows. BAAL_(Low) represents theLow Balancing Authority ACE Limit (MW). BAAL_(High) represents the HighBalancing Authority ACE Limit in MW. B_(i) represents the Frequency BiasSetting for a Balancing Authority in MW/0.1 Hz. F_(A) represents themeasured frequency in Hz. F_(S) represents the scheduled frequency inHz. FTL_(Low) represents the Low Frequency Trigger Limit (calculated asF_(S)−3ε₁) in Hz. FTL_(High) represents the High Frequency Trigger Limit(calculated as F_(S)+3ε₁) in Hz. ε₁ represents the constant derived froma targeted frequency bound for each Interconnection (same as theconstant used in the CPS1 calculations above).

The actual frequency trend is monitored. The necessary condition toapply BAAL control is that the actual frequency consistently stays above(or below) the scheduled frequency, and accordingly only BAAL_(High) (orBAAL_(Low)) is applicable. Since the control objective is to bring theclock-minute ACE below BAAL_(High) (or above BAAL_(Low)) within at most30 minutes to avoid penalty, each control area may have its own timetarget which is less than 30 minutes for some safety margin to bring theclock-minute average ACE to comply with the applicable BAAL.

Let the time target be T_(BAAL) (T_(BAAL)<30) minutes. Let the number ofminutes over which the clock-minute average violates the applicable BAAL(use BAAL instead of mentioning explicitly BAAL_(High) or BAAL_(Low)) bedenoted by T_(BAAL) ^(Past). Since over any of the remaining(T_(BAAL)−T_(BAAL) ^(Past)) clock-minutes, if the control action is ableto bring the clock-minute average ACE to comply with the BAAL, then thecontrol area is BAAL compliant. Note that the BAAL control reallyreduces to single clock-minute average ACE correction irrespective ofprevious clock-minute ACE averages. This makes Proportional Control anatural choice to correct clock-minute ACE for BAAL compliance.

In some embodiments, the control scheme can be defined as follows. IfBAAL_(High) is violated, then the correction is

${BAAL\_ Correction} = {- {k_{11}\left( {{ACE} - {\frac{T_{BAAL} - T_{BAAL}^{Past}}{T_{BAAL}}\left( {{BAAL}_{High} - {db}_{BAAL}} \right)}} \right)}}$where k₁₁ is positive and tunable with a default value of 1.0 anddb_(BAAL) is a positive deadband. Notice that as time progresses, thecorrection becomes more aggressive. If BAAL_(Low) is violated, then thecorrection is

${BAAL\_ Correction} = {- {k_{12}\left( {{ACE} - {\frac{T_{BAAL} - T_{BAAL}^{Past}}{T_{BAAL}}\left( {{BAAL}_{Low} - {db}_{BAAL}} \right)}} \right)}}$where k₁₂ is positive and tunable with a default value of 1.0.

The improved LFC module of embodiments of the present invention utilizesa real-time operational database for fast data I/O. The following dataelements are used by the improved LFC module to implement coordinatedCPS control. The data includes historical data from a HistoricalInformation System (HIS) including ACE, frequency deviation, interchangeerror, frequency bias for the current month and past 12 months. Thatdata also includes static data including constant values such as ε₁,ε₁₀, etc. The data further includes dynamic input data such as real-timemeasurements, calculated values, and user input data such as CurrentACE, Current frequency, Frequency bias, Current net interchange, Netinterchange schedule, Control area's CPS1 performance target, Controlarea's CPS2 performance target (applicable when CPS2 is used and notapplicable when BAAL compliance is used). Other data types includeworking data that has been pre-processed by LFC to set up theformulation of the CPS based optimized control model and output dataresulting from solving the optimized CPS control, i.e., the desiredgeneration and system regulation.

In some embodiments, the improved LFC module can be implemented in twoparts. The first part is an LFC application that does datapre-processing and prepares data in a form that can be accepted by theCoordinated CPS Control engine. The LFC application also obtains thesolution results from the Coordinated CPS Control engine, performspost-processing, and stores the results into the operational databasefor implementation as regulation corrections. The second part is theCoordinated CPS Control Engine. This part includes the performancestandards functions described in detail above and which are callablefrom within the LFC application. The Coordinated CPS Control Enginereceives various input data, computes optimal CPS control solutions, andstores the solution results into the LFC application supplied outputdata structures.

Turning now to FIG. 3, an example method 300 of controlling an energydelivery system according to embodiments of the invention is depicted ina flow chart. Within an AGC system of an EMS, an LFC module prepares andpasses area data and unit data to a Coordinated CPS Control engine thatimplements the above described performance control functions (302). Thedata can be retrieved from the real-time CPS database and includes thehistorical, static, and dynamic input data described above. TheCoordinated CPS Control engine determines and allocates the memoryneeded (304), and then reformats the data into useable arrangements andbuilds any needed indexes (306). Next, based on the performancestandards being used, the appropriate performance standards functionswithin the Coordinated CPS Control engine are executed using the inputdata (308). The Coordinated CPS Control engine maps the resultingsolution into output data structures provided by the LFC application(310). The Coordinated CPS Control engine releases the memory it usedand cleans up (e.g., resets for subsequent executions) (312). The LFCApplication accesses the solution results in the output data structures(314) and indicates the system regulation corrections to be made by theAGC based on the solution results, for example, by storing the solutionresults in the operational database (316).

FIG. 4 depicts details of selecting the appropriate performancestandards functions within the Coordinated CPS Control engine to executewhile performing the above described method 300. In all cases, the ShortTerm CPS1 and Long Term CPS1 Control functions are executed (402). Flowproceeds based on the pre-selected performance standard being used,either CPS2 or BAAL (404). If CPS2 is in use, the Short Term CPS2Control function is executed (406). IF BAAL is in use, the BAAL Controlfunction is executed (408).

Numerous embodiments are described in this disclosure, and are presentedfor illustrative purposes only. The described embodiments are not, andare not intended to be, limiting in any sense. The presently disclosedinvention(s) are widely applicable to numerous embodiments, as isreadily apparent from the disclosure. One of ordinary skill in the artwill recognize that the disclosed invention(s) may be practiced withvarious modifications and alterations, such as structural, logical,software, and electrical modifications. Although particular features ofthe disclosed invention(s) may be described with reference to one ormore particular embodiments and/or drawings, it should be understoodthat such features are not limited to usage in the one or moreparticular embodiments or drawings with reference to which they aredescribed, unless expressly specified otherwise.

The present disclosure is neither a literal description of allembodiments nor a listing of features of the invention that must bepresent in all embodiments.

The Title (set forth at the beginning of the first page of thisdisclosure) is not to be taken as limiting in any way as the scope ofthe disclosed invention(s).

The term “product” means any machine, manufacture and/or composition ofmatter as contemplated by 35 U.S.C. § 101, unless expressly specifiedotherwise.

Each process (whether called a method, class behavior, algorithm orotherwise) inherently includes one or more steps, and therefore allreferences to a “step” or “steps” of a process have an inherentantecedent basis in the mere recitation of the term ‘process’ or a liketerm. Accordingly, any reference in a claim to a ‘step’ or ‘steps’ of aprocess has sufficient antecedent basis.

When an ordinal number (such as “first”, “second”, “third” and so on) isused as an adjective before a term, that ordinal number is used (unlessexpressly specified otherwise) merely to indicate a particular feature,such as to distinguish that particular feature from another feature thatis described by the same term or by a similar term. For example, a“first widget” may be so named merely to distinguish it from, e.g., a“second widget”. Thus, the mere usage of the ordinal numbers “first” and“second” before the term “widget” does not indicate any otherrelationship between the two widgets, and likewise does not indicate anyother characteristics of either or both widgets. For example, the mereusage of the ordinal numbers “first” and “second” before the term“widget” (1) does not indicate that either widget comes before or afterany other in order or location; (2) does not indicate that either widgetoccurs or acts before or after any other in time; and (3) does notindicate that either widget ranks above or below any other, as inimportance or quality. In addition, the mere usage of ordinal numbersdoes not define a numerical limit to the features identified with theordinal numbers. For example, the mere usage of the ordinal numbers“first” and “second” before the term “widget” does not indicate thatthere must be no more than two widgets.

When a single device, component, structure, or article is describedherein, more than one device, component, structure or article (whetheror not they cooperate) may alternatively be used in place of the singledevice, component or article that is described. Accordingly, thefunctionality that is described as being possessed by a device mayalternatively be possessed by more than one device, component or article(whether or not they cooperate).

Similarly, where more than one device, component, structure, or articleis described herein (whether or not they cooperate), a single device,component, structure, or article may alternatively be used in place ofthe more than one device, component, structure, or article that isdescribed. For example, a plurality of computer-based devices may besubstituted with a single computer-based device. Accordingly, thevarious functionality that is described as being possessed by more thanone device, component, structure, or article may alternatively bepossessed by a single device, component, structure, or article.

The functionality and/or the features of a single device that isdescribed may be alternatively embodied by one or more other devicesthat are described but are not explicitly described as having suchfunctionality and/or features. Thus, other embodiments need not includethe described device itself, but rather can include the one or moreother devices which would, in those other embodiments, have suchfunctionality/features.

Devices that are in communication with each other need not be incontinuous communication with each other, unless expressly specifiedotherwise. On the contrary, such devices need only transmit to eachother as necessary or desirable, and may actually refrain fromexchanging data most of the time. For example, a machine incommunication with another machine via the Internet may not transmitdata to the other machine for weeks at a time. In addition, devices thatare in communication with each other may communicate directly orindirectly through one or more intermediaries.

A description of an embodiment with several components or features doesnot imply that all or even any of such components and/or features arerequired. On the contrary, a variety of optional components aredescribed to illustrate the wide variety of possible embodiments of thepresent invention(s). Unless otherwise specified explicitly, nocomponent and/or feature is essential or required.

Further, although process steps, algorithms or the like may be describedin a sequential order, such processes may be configured to work indifferent orders. In other words, any sequence or order of steps thatmay be explicitly described does not necessarily indicate a requirementthat the steps be performed in that order. The steps of processesdescribed herein may be performed in any order practical. Further, somesteps may be performed simultaneously despite being described or impliedas occurring non-simultaneously (e.g., because one step is describedafter the other step). Moreover, the illustration of a process by itsdepiction in a drawing does not imply that the illustrated process isexclusive of other variations and modifications thereto, does not implythat the illustrated process or any of its steps are necessary to theinvention, and does not imply that the illustrated process is preferred.

Although a process may be described as including a plurality of steps,that does not indicate that all or even any of the steps are essentialor required. Various other embodiments within the scope of the describedinvention(s) include other processes that omit some or all of thedescribed steps. Unless otherwise specified explicitly, no step isessential or required.

Although a product may be described as including a plurality ofcomponents, aspects, qualities, characteristics and/or features, thatdoes not indicate that all of the plurality are essential or required.Various other embodiments within the scope of the described invention(s)include other products that omit some or all of the described plurality.

An enumerated list of items (which may or may not be numbered) does notimply that any or all of the items are mutually exclusive, unlessexpressly specified otherwise. Likewise, an enumerated list of items(which may or may not be numbered) does not imply that any or all of theitems are comprehensive of any category, unless expressly specifiedotherwise. For example, the enumerated list “a computer, a laptop, aPDA” does not imply that any or all of the three items of that list aremutually exclusive and does not imply that any or all of the three itemsof that list are comprehensive of any category.

Headings of sections provided in this disclosure are for convenienceonly, and are not to be taken as limiting the disclosure in any way.

“Determining” something can be performed in a variety of manners andtherefore the term “determining” (and like terms) includes calculating,computing, deriving, looking up (e.g., in a table, database or datastructure), ascertaining, recognizing, and the like.

A “display” as that term is used herein is an area that conveysinformation to a viewer. The information may be dynamic, in which case,an LCD, LED, CRT, Digital Light Processing (DLP), rear projection, frontprojection, or the like may be used to form the display.

The present disclosure may refer to a “control system”, application, orprogram. A control system, application, or program, as that term is usedherein, may be a computer processor coupled with an operating system,device drivers, and appropriate programs (collectively “software”) withinstructions to provide the functionality described for the controlsystem. The software is stored in an associated memory device (sometimesreferred to as a computer readable medium). While it is contemplatedthat an appropriately programmed general purpose computer or computingdevice may be used, it is also contemplated that hard-wired circuitry orcustom hardware (e.g., an application specific integrated circuit(ASIC)) may be used in place of, or in combination with, softwareinstructions for implementation of the processes of various embodiments.Thus, embodiments are not limited to any specific combination ofhardware and software.

A “processor” means any one or more microprocessors, Central ProcessingUnit (CPU) devices, computing devices, microcontrollers, digital signalprocessors, or like devices. Exemplary processors are the INTEL PENTIUMor AMD ATHLON processors.

The term “computer-readable medium” refers to any statutory medium thatparticipates in providing data (e.g., instructions) that may be read bya computer, a processor or a like device. Such a medium may take manyforms, including but not limited to non-volatile media, volatile media,and specific statutory types of transmission media. Non-volatile mediainclude, for example, optical or magnetic disks and other persistentmemory. Volatile media include DRAM, which typically constitutes themain memory. Statutory types of transmission media include coaxialcables, copper wire and fiber optics, including the wires that comprisea system bus coupled to the processor. Common forms of computer-readablemedia include, for example, a floppy disk, a flexible disk, hard disk,magnetic tape, any other magnetic medium, a CD-ROM, Digital Video Disc(DVD), any other optical medium, punch cards, paper tape, any otherphysical medium with patterns of holes, a RAM, a PROM, an EPROM, aFLASH-EEPROM, a USB memory stick, a dongle, any other memory chip orcartridge, a carrier wave, or any other medium from which a computer canread. The terms “computer-readable memory” and/or “tangible media”specifically exclude signals, waves, and wave forms or other intangibleor non-transitory media that may nevertheless be readable by a computer.

Various forms of computer readable media may be involved in carryingsequences of instructions to a processor. For example, sequences ofinstruction (i) may be delivered from RAM to a processor, (ii) may becarried over a wireless transmission medium, and/or (iii) may beformatted according to numerous formats, standards or protocols. For amore exhaustive list of protocols, the term “network” is defined belowand includes many exemplary protocols that are also applicable here.

It will be readily apparent that the various methods and algorithmsdescribed herein may be implemented by a control system and/or theinstructions of the software may be designed to carry out the processesof the present invention.

Where databases and/or data structures are described, it will beunderstood by one of ordinary skill in the art that (i) alternativedatabase structures to those described may be readily employed, and (ii)other memory structures besides databases may be readily employed. Anyillustrations or descriptions of any sample databases/data structurepresented herein are illustrative arrangements for storedrepresentations of information. Any number of other arrangements may beemployed besides those suggested by, e.g., tables illustrated indrawings or elsewhere. Similarly, any illustrated entries of thedatabases represent exemplary information only; one of ordinary skill inthe art will understand that the number and content of the entries canbe different from those described herein. Further, despite any depictionof the databases as tables, other formats (including relationaldatabases, object-based models, hierarchical electronic file structures,and/or distributed databases) could be used to store and manipulate thedata types described herein. Likewise, object methods or behaviors of adatabase can be used to implement various processes, such as thosedescribed herein. In addition, the databases may, in a known manner, bestored locally or remotely from a device that accesses data in such adatabase. Furthermore, while unified databases may be contemplated, itis also possible that the databases may be distributed and/or duplicatedamongst a variety of devices.

As used herein a “network” generally refers to an energy deliverynetwork. However, in some embodiments, an information or computingnetwork can be used that provides an environment wherein one or morecomputing devices may communicate with one another. Such devices maycommunicate directly or indirectly, via a wired or wireless medium suchas the Internet, LAN, WAN or Ethernet (or IEEE 802.3), Token Ring, orvia any appropriate communications means or combination ofcommunications means. Exemplary protocols include but are not limitedto: Bluetooth™, Time Division Multiple Access (TDMA), Code DivisionMultiple Access (CDMA), Global System for Mobile communications (GSM),Enhanced Data rates for GSM Evolution (EDGE), General Packet RadioService (GPRS), Wideband CDMA (WCDMA), Advanced Mobile Phone System(AMPS), Digital AMPS (D-AMPS), IEEE 802.11 (WI-FI), IEEE 802.3, SAP, thebest of breed (BOB), system to system (S2S), or the like. Note that ifvideo signals or large files are being sent over the network, abroadband network may be used to alleviate delays associated with thetransfer of such large files, however, such is not strictly required.Each of the devices is adapted to communicate on such a communicationmeans. Any number and type of machines may be in communication via thenetwork. Where the network is the Internet, communications over theInternet may be through a website maintained by a computer on a remoteserver or over an online data network including commercial onlineservice providers, bulletin board systems, and the like. In yet otherembodiments, the devices may communicate with one another over RF, cableTV, satellite links, and the like. Where appropriate encryption or othersecurity measures such as logins and passwords may be provided toprotect proprietary or confidential information.

Communication among computers and devices may be encrypted to insureprivacy and prevent fraud in any of a variety of ways well known in theart. Appropriate cryptographic protocols for bolstering system securityare described in Schneier, APPLIED CRYPTOGRAPHY, PROTOCOLS, ALGORITHMS,AND SOURCE CODE IN C, John Wiley & Sons, Inc. 2d ed., 1996, which isincorporated by reference in its entirety.

It will be readily apparent that the various methods and algorithmsdescribed herein may be implemented by, e.g., appropriately programmedgeneral purpose computers and computing devices. Typically a processor(e.g., one or more microprocessors) will receive instructions from amemory or like device, and execute those instructions, therebyperforming one or more processes defined by those instructions. Further,programs that implement such methods and algorithms may be stored andtransmitted using a variety of media (e.g., computer readable media) ina number of manners. In some embodiments, hard-wired circuitry or customhardware may be used in place of, or in combination with, softwareinstructions for implementation of the processes of various embodiments.Thus, embodiments are not limited to any specific combination ofhardware and software. Accordingly, a description of a process likewisedescribes at least one apparatus for performing the process, andlikewise describes at least one computer-readable medium and/or memoryfor performing the process. The apparatus that performs the process caninclude components and devices (e.g., a processor, input and outputdevices) appropriate to perform the process. A computer-readable mediumcan store program elements appropriate to perform the method.

The present disclosure provides, to one of ordinary skill in the art, anenabling description of several embodiments and/or inventions. Some ofthese embodiments and/or inventions may not be claimed in the presentapplication, but may nevertheless be claimed in one or more continuingapplications that claim the benefit of priority of the presentapplication. Applicants intend to file additional applications to pursuepatents for subject matter that has been disclosed and enabled but notclaimed in the present application.

The foregoing description discloses only exemplary embodiments of theinvention. Modifications of the above disclosed apparatus and methodswhich fall within the scope of the invention will be readily apparent tothose of ordinary skill in the art. For example, although the examplesdiscussed above are illustrated for an electricity market, embodimentsof the invention can be implemented for other markets.

Accordingly, while the present invention has been disclosed inconnection with exemplary embodiments thereof, it should be understoodthat other embodiments may fall within the spirit and scope of theinvention, as defined by the following claims.

What is claimed is:
 1. A method of controlling an energy deliverysystem, the method comprising: providing an energy management system(EMS) at an Independent System Operator (ISO) control center, the EMShaving an automatic generation control (AGC) system including a loadfrequency control (LFC) module; providing one or more communicationpaths between the AGC of the EMS and each one of one or more electricalpower generating resources remote from the EMS; executing two or moreperformance standard functions implemented within the LFC module usinginput data regarding the energy delivery system, wherein at least one ofthe performance standard functions is defined to be dependent uponanother of the performance standard functions; generating solutionresults based on executing the performance standard functions; andtransmitting instructions to implement corrections, based at least inpart on the solution results, via the one or more communication paths toat least one of the one or more electrical power generating resourcesremote from the EMS.
 2. The method of controlling an energy deliverysystem of claim 1, wherein the performance standard functionsimplemented within the LFC module include a Long Term North AmericanElectric Reliability Corporation (NERC) Control Performance Standard 001(CPS1) Control function, a Short Term CPS1 Control function, a Long TermNERC Control Performance Standard 002 (CPS2) Control function, and aShort Term CPS2 Control function, wherein Long Term refers to a timeperiod of greater than a month and Short Term refers to a time periodless than ten minutes.
 3. The method of controlling an energy deliverysystem of claim 2, wherein the Long Term CPS1 Control function and theLong Term CPS2 Control function are integrated, and wherein the ShortTerm CPS1 Control function and the Short Term CPS2 Control areintegrated.
 4. The method of controlling an energy delivery system ofclaim 1, wherein the performance standard functions implemented withinthe LFC module include a Long Term CPS1 Control function, a Short TermCPS1 Control function, and a NERC Balancing Authority Area Control Error(ACE) Limit (BAAL) Control function, wherein Long Term refers to a timeperiod of greater than a month and Short Term refers to a time periodless than ten minutes.
 5. The method of claim 4, wherein the BAALControl function is operative to calculate a clock-minute ACE and aclock-minute BAAL, monitor a clock-minute ACE average, and initiate acontrol action to correct the ACE back to the clock-minute BAALresponsive to the ACE exceeding the clock-minute BAAL.
 6. The method ofcontrolling an energy delivery system of claim 1, wherein the input dataincludes historical data, static data, and dynamic data.
 7. The methodof controlling an energy delivery system of claim 1, wherein providingthe LFC module includes providing an LFC application and a coordinatedCPS control engine, and wherein the LFC application is operative to callthe performance standard functions in the coordinated CPS controlengine.
 8. A system comprising: a process controller; one or morecommunication paths coupled between the process controller and one ormore electrical power generating resources of an energy delivery system;a memory coupled to the process controller and having instructionsstored therein that, when executed by the process controller, cause theprocess controller to: execute two or more performance standardfunctions using input data regarding an energy delivery system, whereinat least one of the performance standard functions is defined to bedependent upon another of the performance standard functions, togenerate solution results; and transmit one or more instructions toimplement corrections via at least one of the one or more communicationpaths to at least one of the one or more electrical power generatingresources of the energy delivery system; wherein the one or moreinstructions are based, at least in part, on the solution results. 9.The system of claim 8, wherein the performance standard functionsimplemented within the LFC module include a Long Term CPS1 Controlfunction, a Short Term CPS1 Control function, a Long Term CPS2 Controlfunction, and a Short Term CPS2 Control function, wherein Long Termrefers to a time period of greater than a month and Short Term refers toa time period less than ten minutes.
 10. The system of claim 9, whereinthe Long Term CPS1 Control function and the Long Term CPS2 Controlfunction are integrated, and wherein the Short Term CPS1 Controlfunction and the Short Term CPS2 Control function are integrated. 11.The system of claim 8, wherein the performance standard functionsinclude a Long Term CPS1 Control function, a Short Term CPS1 Controlfunction, and a BAAL Control function, wherein Long Term refers to atime period of greater than a month and Short Term refers to a timeperiod less than ten minutes.
 12. The system of claim 11, wherein theBAAL Control function is operative to calculate a clock-minute ACE and aclock-minute BAAL, monitor a clock-minute ACE average, and initiate acontrol action to correct an ACE back to the clock-minute BAALresponsive to the ACE exceeding the clock-minute BAAL.
 13. The system ofclaim 8, wherein the input data includes historical data, static data,and dynamic data.
 14. The system of claim 8, further comprising: an LFCapplication and a coordinated CPS control engine, wherein the LFCapplication is operative to call the performance standard functions inthe coordinated CPS control engine.
 15. A system, comprising: a loadfrequency control (LFC) application stored within the system that, whenexecuted by a process controller, causes the process controller togenerate an output data structure and to store solution results in anoperational database of an energy management system (EMS); a coordinatedCPS control engine stored within the system that, when executed by theprocess controller, causes the process controller to receive input data,execute two or more performance standard functions called by the LFCapplication, and to populate the output data structure with solutionresults; and one or more communication paths coupled between the processcontroller and one or more electrical power generating resources, theone or more communication paths configured to carry instructions fromthe process controller to at least one of the one or more electricalpower generating resources to implement corrections; wherein at leastone of the performance standard functions executable by the coordinatedCPS control engine is defined to be dependent upon another of theperformance standard functions.
 16. The system of claim 15, wherein theperformance standard functions implemented within the coordinated CPScontrol engine include a Long Term CPS1 Control function, a Short TermCPS1 Control function, a Long Term CPS2 Control function, and a ShortTerm CPS2 Control function.
 17. The system of claim 16, wherein the LongTerm CPS1 Control function and the Long Term CPS2 Control function areintegrated, and wherein the Short Term CPS1 Control function and theShort Term CPS2 Control function are integrated.
 18. The system of claim15, wherein the performance standard functions implemented within thesystem include a Long Term CPS1 Control function, a Short Term CPS1Control function, and a BAAL Control function.
 19. The system of claim18, wherein the BAAL Control function is operative to calculate aclock-minute ACE and a clock-minute BAAL, monitor a clock-minute ACEaverage, and initiate a control action to correct an ACE back to theclock-minute BAAL responsive to the ACE exceeding the clock-minute BAAL.20. The system of claim 15, wherein the system is communicativelycoupled to a CPS database within a historical information system runningon a second process controller.